Over the years, water conservation requirements have been imposed on residential toilets. Formerly, when no water usage limits were imposed, toilets were built with tanks containing about five gallons. A single flushing apparatus dispensed most of this water. Later, the amount of water stored and dispensed was reduced to about 1.6 gallons per flush.
In conventional toilets the water for flushing is held in a tank mounted higher than the toilet bowl and flows from the tank into the bowl when the user opens a valve between the two by depressing a control lever. In some such toilets (usually called flapper toilets) the linkage from the lever to the valve, and the valve itself, are designed so that the valve drops partly or entirely back into its seat, reducing or stopping the flushing, as the user partly or entirely releases the control lever. However, in most conventional toilets, the linkage from the control lever to the valve, and the valve itself, are designed so that as soon as the user depresses the control lever by more than a very minimal amount the valve floats completely off of its seat and the flow of water from the tank into the bowl cannot be reduced or stopped by the user but water flow stops only when the water level in the tank falls almost to the empty level, thereby allowing the valve to sink back to its seat. The present invention pertains to the latter type of toilet.
Conserving water in a conventional toilet has been attempted using expedients such as placing bricks in the tank to reduce tank capacity, and bending float rods to lower the water level in the tank. However, none of these prior art efforts have proven entirely satisfactory.
Another factor in water conservation is the effectiveness of the flush valve action. Valves may fail to seat properly, thereby continuously leaking tank water into the toilet between flushes. This can account for considerable waste of water over the course of a year.
Another attempt at water conservation is using a dual flush lever arrangement, one for relatively great volume flushes and the other for small volume flushes to control the amount of water used.
It would therefore be desirable to have an apparatus that adjustably limits the amount of water used in a conventional toilet by giving the user control over the volume and flow rate of water being released for each flush, and promoting effective seating of the valve following the flush.
Although water conservation achievable by the toilet user's having control of the rate and amount of flushing is of prime importance, it is desirable in some circumstances to have the toilet flushing operate without the user's exercising such control. This may be the case if, for example, the toilet is to be used by a young child, an infirm person, a house guest, or a visitor to a public establishment. It would therefore be desirable to be able to reversibly convert the toilet easily and without expense between the mode in which the user controls the rate and amount of water flow and the mode in which he or she does not.